Polyvinyl acetal plastic compositions



Patented June 1 2, l9"4l5 El'mer R, Derby,Springfield, Mass..assignor, by .mesne assignments, to Monsanto Chemical Company, S,t.-Louis,'Mo., a: corporation of Delaware No Drawing. 7 Original application November 2,

1937, Serial No. a; plication January 172,442. Divided and this ap- 22, 1942, Serial No.427'5719 2-Claims. (01. 250-36) My present invention relates to plasticm'aterial to be employedas interleaf material in the manuiactureof safety glass and the like. Asis well,

known to those skilled in the art, polyvinyl acetal resin, 1. e. a material made by condensing an aldehyde'with a partially hydrolized polyvinyl acetate suchas the resin described in the patent to Morrison et al. Reissue No. 20,430, dated June 29. 1937 appears tobe an excellent if not the best material known for the purpose mentioned pro- ,vided it is mixed with a satisfactory plasticizer but its utilization has been retarded by the difliculty which has been experienced in discover.- ering a plasticizer which will give to the final product the necessary properties.

These resins vary in the proportion of hydroxyl groups and acetate groups which they contain with respect to the acetal. .For instance: a satisfactory resin made with formaldehyde contains 82% acetal, 8% hydroxyl groups figured aspolyvinyl alcohol and 10% acetate. Anothersatisfactory resin contains from to 2% acetate, '16 to 20% hydroxyl groups figured as polyvinyl alcohol and the balance acetal formed with'butyraldehyde. The different resins of which the'foregoing:are only two examplesihave differentiproperrties according to the proportion of thethree substituents mentioned and the particular :aldehyde employed. I 7 c In a companion application Serial No. l72;443

, filed Nov. 2, 1937 I have described the important discovery that the most satisfactory plasticizer of a given chemical series of plasticizersis that one which is most nearly incompatible 'with'the particular resin employed and yet is miscible with .I have also discovered that certain substances, particularly esters, which are not themselves compatible with the resin in the proportions required,

for good quality plastic for safety glass, oan'be rendered compatible with polyvinyl-acetal resin and willhave'the efiect of plasticizing the resin and of producing a material which is useful for the purposes specifled'provided there is alsopresent in the mixture 9. suitable quantity of a second plasticizer which. in the proportionused-is miscible both with the resin and the first plasticizer to produce a homogeneous plastic. It will be unv 'derstood that when I refer to incompatibility of .mix homogeneously instead separating as an oily exudation or'tiny droplets causing haze. While the second plasticizer is'often miscible in all proportions with the resin I have-found quite unexpectedly that in some cases, as in Example l below, .both plastici zers may aloheinthe proportion requiredifor good. quality be 7 immiscible if used plastic for safety glass but a miscible mixturecan be "usable as plasticizers.

be made in which the'two plasticizers are so-proportloned that the mixture-is nearly incompatible in the amount required for good safety glass plastic.

Asa result of this discovery I:am able to use of their incompatibility with'theresin, also cervtain substances which have notbeen thoughtto For instance, .30 1 parts dibutyl diglycollateis incompatible with 100 parts of a polyvinyl acetal resin-made withgformaldehyde and containing 82% acetal,.8% hydroxyl tate,;but ifphenyl ethyl alcoholis added in sufful y, obtaining factory and usefulproduct. "For convenience,athe

.phthalate 40 parts and 'parts. Dibutyl phthalate 'diglycol dibutyrate 50 alcohol 2% to 5 parts.

groups figured aspolyvinyl alcohol and 10% aceficient quantity, ,for example, 15 .parts, even 50 partsof dibutyl diglycollate'canbe used successmiselbility' and producing alsatisplasticizer which is relatively incompatible with the-resin may be referred-to as :the non-compatibleplasticizer, and the other. as the solvent plas- .ticizer. The following are other specific examples of=mixtures embodying my-invention:

l. Polyvinyl acetal resin made with-formaldehyde and containing about 82% acetal,'8% hy- V droxyl groups figured as polyvinyl alcohol and 10% .acetate, 100 :parts, mixed "with dibutyl .phenyl ethyl alcohol 40 is normally. incompatible with this polyvinylacetal resin,.but isrendered so by the phenyl ethyl alcohol.

'2.The same polyvinyl acetal resin 100 parts, parts and phenyl ethyl The diglycol dibutyl-ate is not compatible .with the acetalresin at 50.parts but '50-parts maybe'employed if combined=wlth phenyl ethyl alcohol and the mixture is rendered entirely stable bythepresence of Sparts only of phenylethylalcohol.

3. The sameresin 100 parts, diglycol dipropionate v30 .parts and butyl carbitol butyrate'30 parts. parts of butyl carbitol .butyrate alone are incompatible.

-4.,A polyvinyl acetal resin made with butyraldehyde and containing 0 to 2% acetate, 16 to 6 20% :hydroxyl groups figured as alcohol and the balance acetal. This resin 100 parts dilauryl phthalate 85 parts and diethylene glycol parts. 5. The same no y inyhacetal resin 100 parts, dilauryl phthalate ,40 parts and dibutyl diglycollate parts. 60 partsof dilauryi phthalate are incompatible.

'6. The same resin 100 parts, amyi laurate 35 parts. dibutyl phthalate parts.v 85 parts of amyl laurate alone are incompatible with this resin.

l. The-same resin imparts, butyl laurate 85 parts, dibutyl phthalate 25 parts. 8. The same resin 100 parts, amyl laurate 60' parts, phenyl ethyl alcohol parts. parts of amyl laurate alone, or 60 parts of amyl laurate plus 15 parts patible. I

ofphenyl ethyl alcohol, are incom- V 9. The same resin 100. parts, butyl laurate 60 parts, phenyl ethyl alcohol 30 parts.

The proportions given above are those which give the most satisfactory final product for the manufacture of safety glass, due regard being had to both the cold break test and the hot break test as Judged by dropping a two pound ball at 0' E, and 120 1., respectively, on an assembly made with. plastic not less than 0.015 inch nor I more than 0.027 inch thick. used in laminated s'lass, each of the materials produced in accordance with the foregoing examples gives substantially equal hot and cold break tests. The

compositions mentioned give results superior to the present vacetate safety glass and fully comparable with the compositions mentioned in the co-pending application mentioned and based on various polyvinyl acetal resins.

The laurates above mentioned may be pure chemical compounds or the esters of cocoanut oil fatty acids, or the esters of cocoanut oil fatty acids from which high boilers have been removed.

The present application is a division of my prior application Serial Number 172,442, filed November 2, 1937.

What is claimed is:

l. A polyvinyl acetal resin made with formaldehyde and plasticized with a mixture of substantially 30 parts diethylene glycol dipropionate and substantially 30 parts butyl carbitol butyrate for each'100 parts of resin.

. 2. A polyvinyl acetal resin plasticized with a mixture of substantially 30 parts diethylene glycol dipropionate and substantially 30 parts butyl carbitol butyrate for each parts of the resin.

ELIVIER R. DERBY. 

